Good on you, sfb.
They are probably no slower than most D1 Bantams - and people claim they are "genuine classics" and advertise them for over a grand!
I rode my sister's Ariel 3 for a short while in the mid 70s, it was a fun commuter.

One incident springs to mind when I was bringing it home from the shop for her.
There was a small roundabout, going down hill.
I had the Ariel flat out, almost 30 mph!, and didn't bother to slow down for the roundabout.
Banked it over elegantly and then found that it wouldn't bank any further!
More by luck (and panic!) than judgement I discovered that if I stood up on the pedals, with the inner pedal raised and maximum opposite lock then the back end slid wide in a sort of oversteer.
Somehow I made it around the roundabout and exited up the correct turning, still flat out.
What worried me more than anything else - while this was happening - was the thought of explaining to my little sister how I had wrecked her new toy before she even got to sit on it.

Still, she must have forgiven me - or maybe taking Gus as her lodger is some sort of revenge?

Well, I've made no progress with no 1 Ariel 3. Having spent months waiting for the appearance of a new engine from Holland, I placed an advert it the NACC magazine for a spare engine & other parts.

As a result of this, I had a phone call offering me not just an engine but a complete Ariel 3 (although the seat was missing). I arranged for one of the subbies at work to collect it for me (having not seen it or any piccies) and a few weeks ago, this is what arrived:

Since then, it has sat in the back garden awaiting its fate........

I had a day off work today, so I decided to attack it and start dismantling it before it falls apart all by itself.

First, I had to remove the birds nest:

It then became clear that the fuel tank was missing!

Next, I had to hacksaw through the bolts holding the lid on the engine enclosure. Once this was done, I detached the carburettor - at first I thought this was incomplete but I was being daft and it is just the airbox that is missing. The nuts holding the carb on came off easily. I then removed the exhaust - again the nuts were easily removed and the exhaust came out with a bit of judicious wiggling. Here it is in all its glory:

With the exhaust removed, I could get to the nuts and blots holding the engine enclosure in place. Again, this was fairly easy and I soon had a naked Ariel 3!

Most bits look to be salvageable but the tank, seat, airbox and the belt for the fan are missing. And I'll clearly need some new tyres!

It's all good fun. I don't have a log book but the reg number can clearly be seen and it still has an old tax disc on it so that ought to be possible.

More piccies here (in case those few aren't sickening enough for you!)